Equations

Question 1

Sensitivity

Answer 1

= TP/ (TP+ FN)

Question 2

Specificity

Answer 2

= TN / (TN + FP)

Question 3

Positive predictive value

Answer 3

= TP / (TP + FP)

Question 4

Negative predictive value

Answer 4

= TN / (FN + TN)

Question 5

Odds ratio (for case control studies)

Answer 5

= (a/c) / (b/d) = ad / bc

Question 6

Relative risk

Answer 6

= (a / (a+b)) / (c / (c+d))

Question 7

Attributable risk

Answer 7

= (a / (a+b)) - (c / (c+d))

Question 8

Relative risk reduction

Answer 8

= 1 - RR

Question 9

Absolute risk reduction

Answer 9

= (c / (c+d)) - (a / (a+b))

Question 10

Number needed to treat

Answer 10

= 1/absolute risk reduction

Question 11

Number needed to harm

Answer 11

= 1/attributable risk

Question 12

Hardy-Weinberg equilibrium

Answer 12

p^2 + 2pq + q^2 = 1

p + q = 1

Question 13

Volume of distribution

Answer 13

= amount of drub in body / plasma drug concentration

Question 14

Half-life

Answer 14

= (0.693 x Vd) / CL

Question 15

Drug clearance

Answer 15

= rate of elimination of drug / plasma drug concentration = Vd x Ke (elimination constant)

Question 16

Loading dose

Answer 16

= (Cp x Vd) / F

Question 17

Maintenance dose

Answer 17

= (Cp x CL x r) / F

Question 18

Cardiac output

Answer 18

= rate of O2 consumption/ (arterial O2 content - venous O2 content) = stroke volume x heart rate

Question 19

Mean arterial pressure

Answer 19

= cardiac output x total peripheral resistance = 2/3 diastolic + 1/3 systolic

Question 20

Stroke volume

Answer 20

= EDV - ESV

Question 21

Ejection fraction

Answer 21

= SV / EDV = (EDV - ESV) / EDV

Question 22

Resistance

Answer 22

= driving pressure / flow

Question 23

Capillary fluid exchange

Answer 23

= net fluid flow = Kf((Pc-Pi) - s(nc-ni))

Question 24

Renal clearance

Answer 24

= UxV / Px

Question 25

Glomerular filtration rate

Answer 25

= Uinulin x V/Pinulin = Cinulin

Question 26

Effective renal plasma flow

Answer 26

= Upah x (V / Ppah) = Cpah

Question 27

Renal blood flow

Answer 27

= RPF / (1 - Hct)

Question 28

Filtration fraction

Answer 28

= GFR/ RPF

Question 29

Henderson Hasselbach equation

Answer 29

pH = 6.1 + log (HCO3 / (0.03 Pco2))

Question 30

Winters formula

Answer 30

Pco2 = 1.5 [HCO3] + 8 +/- 2

Question 31

Physiologic dead space

Answer 31

= Vt x ((Paco2 - Peco2) / Paco2)

Question 32

Pulmonary vascular resistance

Answer 32

= (P pulm artery - P left atrium) / cardiac output

Question 33

Alveolar gas equation

Answer 33

= Pio2 - (Paco2 / R)